Present circuit fabrication lends itself to the creation of integrated circuits requiring biasing and initiation by a specific current or voltage value. To help bias and initiate these integrated circuits, self-biasing circuits, often called band-gap reference circuits (band-gaps), are implemented.
Band-gaps are used in a variety of integrated circuit devices as a means for generating a temperature and supply independent reference voltage, as well as a temperature and supply independent current. The band-gap provides the rest of the chip upon which it is situated with reference voltages and currents. Hence, if the band-gap doesn't start up on its own, the entire chip, and the system it is connected to, may fail to operate.
Therefore, a critical issue in the design of band-gaps is ensuring that the band-gap starts promptly and that any chance of the band-gap not starting is significantly reduced, if not eliminated altogether. To fulfill these requirements, start-up circuitry is implemented.
Several known techniques are presumably utilized to start band-gaps. Amongst these, conventional approaches have attempted to design a solution to force the self-biased circuit out of any low power state, which will not allow the self-biased circuit to start, by utilizing devices which are capable of functioning with low power. This, however, is very difficult and highly unreliable, as the properties of the low power devices cannot be properly modeled by simulation programs in this low power mode due to the simulation programs being generally incapable of accepting such low power values for parameter requirements.
Therefore, there is a need for a reliable and efficient method for initiating bandgaps.